English

Equations of some embeddings of a projective space into another one

Commutative Algebra 2020-12-11 v1 Algebraic Geometry

Abstract

In arXiv:math/0405373 , Eisenbud, Huneke and Ulrich conjectured a result on the Castelnuovo-Mumford regularity of the embedding of a projective space Pn1Pr1\mathbb{P}^{n-1}\hookrightarrow \mathbb{P}^{r-1} determined by generators of a linearly presented m\mathfrak{m}-primary ideal. This result implies in particular that the image is scheme defined by equations of degree at most nn. In this text we prove that the ideal of maximal minors of the Jacobian dual matrix associated to the input ideal defines the image as a scheme; it is generated in degree nn. Showing that this ideal has a linear resolution would imply that the conjecture in arXiv:math/0405373 holds. Furthermore, if this ideal of minors coincides with the one of the image in degree nn - what we hope to be true - the linearity of the resolution of this ideal of maximal minors is equivalent to the conjecture in arXiv:math/0405373.

Keywords

Cite

@article{arxiv.2012.05681,
  title  = {Equations of some embeddings of a projective space into another one},
  author = {Marc Chardin and Navid Nemati},
  journal= {arXiv preprint arXiv:2012.05681},
  year   = {2020}
}